Rapeseed or linseed supplements in grass-based diets: Effects on milk fatty acid composition of Holstein cows over two consecutive lactations

Abstract

Persistency of changes in milk fatty acid (FA) composition to 4 different oilseed supplements rich in cis-9 18:1 or 18:3n-3 was determined over 2 consecutive lactations in 58 and 35 Holstein cows during the first and second years, respectively. During the initial 5 wk of the study, all experimental cows were fed the same diet. Thereafter, cows received 1 of 5 treatments for 2 consecutive lactations, including the prepartum period. Treatments comprised the basal diet with no additional lipid, or supplements of extruded linseeds (EL), extruded rapeseeds (ER), cold-pressed fat-rich rapeseed meal (FRM), or whole unprocessed rapeseeds (WR). Oilseeds were offered to provide between 2.5 to 3.0% of additional oil in diet dry matter. During indoor periods, cows received a mixture (3:1, wt/wt) of grass silage and grass hay, whereas cows were at pasture during outdoor periods. Over the entire study, oilseed supplements decreased the concentration of milk FA synthesized de novo and increased 18:0 and cis-9 18:1 content, with a ranking of treatment responses (highest to lowest) of FRM, EL, ER, and WR. Irrespective of period, both EL and FRM increased total milk trans FA content, whereas WR resulted in lower concentrations in milk from grazing cows. Relative to rapeseed, EL resulted in higher increases in milk cis-12,cis-15,trans-12 to -16 18:1, nonconjugated trans 18:2 (especially ∆11,15), and 18:3n-3. In contrast, rapeseed supplements resulted in a greater enrichment of cis-11 18:1, trans-4 to -9 18:1, and cis 20:1 than EL. Changes in milk FA composition to oilseeds were of greater magnitude during indoor than outdoor periods, where oilseed supplements often decreased cis-9,trans-11 conjugated linoleic acid content. During the second indoor period, both EL and ER resulted in higher total trans FA content, trans-10 18:1 in particular, than during the first indoor period, consistent with an interaction between dietary starch content and oilseed supplement. Overall, the extent of changes in milk FA composition were related to the nature (rapeseed or linseed) and form of oilseed (extruded, cold-pressed fat-rich meal or whole unprocessed), and their interactions with the composition of the basal diet (grass silage and hay or pasture; or dietary starch content). Milk FA responses were stable within each period and repeatable over both outdoor feeding periods, with extent of changes being comparable to reports from relatively short-term (1- to 3-mo) studies.

Bovine Mammary Nutrigenomics and Changes in the Milk Composition due to Rapeseed or Sunflower Oil Supplementation of High-Forage or High-Concentrate Diets

“…These results are in line with those reported previously [21]. Regarding RS supplementation, the observed reductions of 37, 23 and 30% in the C12:0, 14:0 and 16:0 concentrations in milk fat are in agreement with the previously reported decreases for these FA under RS supplementation [23,24]. In the present study, the concentration of cis-9 C18:1 was markedly increased, whereas that of cis-9,trans-11 CLA was not affected by RS supplementation, as observed by Lerch et al [24].…”

“…Regarding RS supplementation, the observed reductions of 37, 23 and 30% in the C12:0, 14:0 and 16:0 concentrations in milk fat are in agreement with the previously reported decreases for these FA under RS supplementation [23,24]. In the present study, the concentration of cis-9 C18:1 was markedly increased, whereas that of cis-9,trans-11 CLA was not affected by RS supplementation, as observed by Lerch et al [24]. Moreover, the addition of RS to the diet led to an increase in the concentrations of all of the measured trans -FA, except for trans-11 C18:1, trans-10 C18:1 and CLA (table 3).…”

Effects of dehydrated lucerne and soya bean meal on milk production and composition, nutrient digestion, and methane and nitrogen losses in dairy cows receiving two different forages

“…Lyophilised morning and evening milks were pooled (60 and 40 mg of morning and evening samples, respectively) to provide a daily composite sample for each cow. FAs in 100 mg samples of lyophilised milk were methylated directly, according to Lerch et al (2012). The fatty acid methyl esters (FAMEs) recovered were analysed by GC using a Trace-GC 2000 Series gas chromatograph equipped with a flame ionisation detector (Thermo Finnigan, Les Ulis, France) and a 100 m fused silica capillary column (i.d.…”

Effects of Linseed Oil or Whole Linseed Supplementation on Performance and Milk Fatty Acid Composition of Lactating Dairy Cows

“…For above reasons, public health guidelines in most developed countries have recommended population-wide reduction in saturated and trans FA and an increase in 18:3n-3, 20:5n-3, and 22:6n-3 in the human food chain to decrease the incidence of chronic disease (WHO, 2003). Although increasing the proportion of polyunsaturated fatty acids (PUFA) in milk is limited due to extensive biohydrogenation of these FA in the rumen, supplementing linseed to dairy cattle increased the proportion of cis -9, trans -11-18:2 ( c 9, t 11 CLA) and n-3 FA, particularly linolenic acid, EPA and DHA in milk (Glasser et al, 2008, Lerch et al, 2012; Puppel et al, 2013). The objective of this study was to characterize milk FA composition responses to different forms of dietary linseed supplements in lactating dairy cows fed a diet based on grass silage.…”